Rotary cutting and granulating machine



Aug. 10, 1943. RODDY 2,326,682

ROTARY CUTTING AND GRANULAIING MACHINE Filed Jan. 7, 1942 3 Sheets-Sheet 1 F13 gj F/PED M. R000) INVENTOR M QLATTORNEY Aug. 10, 1943. F. M. RODDY v 2,3265682 ROTARY CUTTING AND GRANULATING MACHINE Filed Jan. 7, 1942 5 Sheets-Sheet 2 60 FRED M. RODDV YIINVENTOR By M Aug. 10, 1943. F. M. RODDY 2,326,632

ROTARY CUTTING AND GRANULATING MACHINE Filed Jan. 7, 1942 3 Sheets-Sheet 5 III/Illa.

F/PED M. PODDV INVENTOR E i iATTORNEY Patented Aug. 10,1943

RorARY mm AND onANULArmG ,1]. I:

@ monmn V Fred M.'R0ddy,-1rovidence, Rl L. 1' Y Applicationdanuary 7, 1942, Serial No. 425,922

5 Glaims.

This invention relates to rotary cutting and granulating machines and, in particular, to a rotary cutting machine especially adapted for the cutting of plastics, for example scraps of thermoplastic materials, to reduce them to predetermined degrees of fineness.

Machines for cutting plastics, for example thermoplastic materials, require a more sturdy and rigid construction than has been employed hitherto in the design of previous cutting machines of this type which operated on materials considerably less difficult to out than plastics. Also, the cutting chambers of machines employed in the cutting of plastics should be as compact as possible so as to stir as small an amount of the material being cutas possible without preventing ready access to the stationary knives or of rendering cleaning of the machine 'difiicult. Also, when the volume of the cutting chamber of the machine is small the material being processed does not remain long in the cutting chamher but is quickly reducedand passes through the screen. A cutting chamber of small volume therefore tends to'avoid abrading the material by stirring or by agitation, thereby providing a percentage of dust which is undesirable in the product. On the other hand, if the cutting chamber has a large volume the 'material is: often stirred in the machine so long that it becomes hot and plasticizes, choking the machine. It has been found that machines havingcuttingcha mbers of but small volume can operate completely full of material without overheating. This is not possible with older types of rotary cutting mae chines.

It has been and is necessary after cutting plastics of various colors to clean the interior cutting (cits-t) chambers of the machine when changingfrom one color to another since a certain amount of dust is produced in the cutting and granulating of plastics and the fines and dust produced frequently collects in all cracks and crevices that may be present in the cutting chambers of the 7 machine Machines Which'are used for cutting of plastics therefore should be designed with an effort to eliminate cracks and crevices in the cutting chambers, and also all parts of the ma chin'e'contacted by the plastics should be made easily accessible in order that the machine may be readily cleaned. "Ease of cleaning therefore becomes of extreme importance in machines which are used for granulating plastics.

One object of the invention is to provide a machine for cutting plastics having a more sturdy and rigid construction than has heretofore been or removing said knives.

'vention;- I

of the cutter unit; and

cutting chambers are as compact as possible'and f devoid of'c'racks and crevices,

Another'object-ofthe inventionisito provide a, V machine of tins 'classfiin which-the adjustable stationary knivesiwill belocated for convenience of adjustment and ease of cleaning ofthe machine. v I 1 Another object of the invention is to. relieve the operator of the necessity of lifting or:supporting theweight of the lower. half of the end'casing while dismantlingthe machine for cleaning. I

Another object of the inventionis the attachment of the lower half of the endcasing .of the machine to the main frame: housing rotatably supporting the rotor, 'wherebythefiattaching means forthe-lower half of. the end casing "will also "act to locate it accurately in; position and insure that the stationary knife adjustment willnot be altered when thealower halfof the end casing is removed and reassembled.

Another-object of theinventionis to provide a construction which avoids putting the stationary knives in machined. slotsas has characterized the construction of Another object of the invention the removal of the screen by lifting it up and out frombetween thestationary knivesof the lower half of the end casing without alterating the adjustment With these and other objects in view as will be apparent in the following specification the invention consists in thenovel 'constructio'nandcombination of the-severalparts as Will-behereinafter fully set forth, and pointed out'in' the claims appended hereto.

In theaoco'rn-panying drawings: Fig.;-1' is aside elevational view-of a motordriven'rotary cutting machine embodying my in- Fig. 2 is an end view of the cutting machine shown in Fig. 1 as viewed from the right;

Fig. 3gis a central'longitudinal sectionallvifew of the'rotar y cutter unit of the cutting machine shown in Fig; 1 H r A Fig. 34: is a transverse sectional view taken substantiallyontheline 44: of Figi'3;

Fig. 5 is a diagrammatic viewpartly in section ,of the rotary cutter unit shown" in' Fig 3 with the hopper and upper casing being repre'sentedin housing frame a detached position from the main Fig. 6 isra transverse-sectiona1 view of the bottom end casing member after removal from the cutter unit'with one of the screensbeing depicted in one positionjof disass'embly;

Generally speaking, the present invention comprises a frotary cutter having an end casing formed of two half 'casingsections superimposed one upon the other and providing a cutting' cham of the base which carries the table. lhe lower half of the end casing is supported by the extension of the table but instead of being aiiixed thereto it is attached to the front end of the with and extending axially from one end of the bearing frame for the knife rotor 'by two large:

horizontal bolts which serve not only as attachingbolts but, also as dowels to locate the lower half of the end casing in position while being assembled and thereby insur that the setting of the stationary knives carried by thelower half of the end casing will not be altered when the lower half of the end'casingis removed and reassem bled. In this machine there are two adjustable stationary .knives which are arranged in the lower half of the end-casing at substantially diametrically opposite positions on the cutting circle .cf the rotary cutting. means, and each of these stationary knives are mounted upon a knife bed, the surface of which is accurately machined and scraped whereby. an accurate fit is obtainedso that no powdered plastic material or dust from the cutting operation can enter and lodge beneath the knives. Aclosure ring is carried by the rotor at the end of the casing near the bearing housing for the rotor, and the upper and lower halves oftheend casings are bolted together and bored accurately so as to give a small clearance be tween this bore and theclosure ring so that both the dust leaking outwardly from the cutting chamberzaround theclosure ring and'any lubricant that, may leak from the forward anti-fric- I tion bearing supporting the rotor will be thrown on into space exteriorly of the machine by cen- ;trifugal force upon impingement with the outer periphery of th closure ring. A; screen is removably mounted in the lower half of the end casing and the screen may be removed by lifting it out from between the stationary knives after the lower half of the .end casing has been removed from the table after removal .of the two large horizontal bolts that attach the lower half of the end casing to the bearing housing for the rotor. I

Referring now ,to the drawings, particularly to Figs. 1 and 2, .a base [.0 includes an enlarged upper table member I l which projects outwardly for a considerable distance beyondone end of the base and presents the overhanging outward extension 12. Mounted at one end portio-nof this .upper table member H was to be-partially supported by the extension l2 thereof and to partially overhang the base I!) is the novel rotary cutter of the present invention which is generally designated by the reference numeral 15. .Suitable driving means for the cutter I 5, here shown as an electric motor 16 provided with a'drive shaft ll, is mounted upon the other end portion of the table member II. The 'drive, shaft H is drivingly connected through flexible coupling is with the rotor shaft 19 of the cutter 15.

body portion 23 of the rotor I9 is the knife carrying head of the rotor comprising. a plurality of radial rotor arms 26, here shown as three in number (see Fig. 4) although any desired number may be employed, upon which are mounted and secured thereto by suitable fastening devices ftheirotor knives 21. In the illustrated embodiment, the knives 21 are on one end of the rotor shaft.

and they overhang the bearings for the rotor As shown, each of the rotor knives 27 is secured to: the rotor head by a pluralityof bolts 28 which pass through suitable holes in the knife and are threaded into the associated =rotorarm26. r

- A sectional lend-casing generally desi 'nated by the reference nulneraliid is provided WLUAiIL-Jflllch the rotor knives 211 revolve. In the form shown in the drawingsthis casing 39 is .composed of the two separable end casing members 3-! and the lower casing member 31 being detachably secured tothe adjacent end of the main frame housing 25 by two large bolts 33. llhe The rotary cutter 15 has a main frame 'hcusing 20 containing suitable anti-friction bearings 2| and 22 (see Fig. 3) in which is journaled the rotor shaft IS. The rotor'shaft I9 is of a generally stepped formation and it extends entirely through the main frame housing bearing suPPQrtframe 20. Mounted upon and secured to the enlarged cylindrical body portion 23 of the rotor shaft I9 is a flywheel ,25 which is f suitable size and weight for overcoming the shocks due to cutting, and for preventing excessivevibration of the machine during running. Formed integrally bolts 33 are preferably designed to fit closely-in both the machine en-cl casing 31 and the-main frame housing 23, so that they serve not only as attaching bolts for-the .lower end casing Si but also as dowels to locatethe lower end casing 31 accurately with .respectto the housing 2.1! and the rotor head thereby .insuring'that the adjustment 'of the stationary knives, hereinafter to be described, will-not be altered when the lower end casing ill is removed .and reassembled. The upper end casin 32 is mounted upon the lower end 'casing 3i and is detachably secured thereto by clamping swing bolts 34 which are pivctally mounted in external recesses :at opposite sides of the end casing 13 1'. The bottom of the upper casing 32 is formed with a semi-cylindrical recess which is concentric with the circular path of the rotor knives Z'i-an'd forms 'the upper part of the cutting chamber 35 of .the machine. The upper end-casing or cover 32 is provided with an inwardly extending feed-ing conduitfifi offset laterally .to the right as viewed in Fig. 4 from :a

vertlcalplaneof the axis of rotation of the rotor is and the lower end of the conduit :35 opens into the cutting chamber 35. 4 .r j

Communicating with the upper end of .the feeding conduit .3fi and rem'ovably fastened to the upperend 0f the upper casing member 32 .by H

clamping swing bolts -31 which are pivotally manned iii suitable external recesses atthe-opposit-e sides cfthe upper casing, is a feed hopper .39 of any suitable construction. '3

At the endiof the casings '3i and 32 where they confront the mainframe housing 28 a closure ring so is .provided'on the rotor shaft; and clearance in the form of an openspace is provided around the closure fring lilso that both the .dust

leaking from the cutting chaniberand any lubrican't that may leak from'the forward anti-friction'b'earin'g' 22 willbe'thrown on into spaceby the action of centrifugal force when it'reacnes the'outer periphery of the closurering and thus cannot work into the cutting chamber to contaminate the plastic material'heing cut therein.

The lower endcas'ing iil carries the two beveled stationary knives M, .the arrangement of which constitutes one of the novel features of the machine, and the knives 141 .are positioned at oppositesides of the rotior'head :and have the tips of their put-ting edges lying in ahorizontal plane containing thea-xis-of the rotor and also disposed on the cutting circle of the rotary knives knives M from backing away fromthe rotor during the-cutting operation and also serve as a means for adjusting the stationary knives inward tothe rotor knives. The knives ll have substantially duplicate structures, and in order to provide for the alignment of their cutting edges when they are mounted in placeato posite sides of the rotor, the recess 53 is made deeper than the opposite recess %2 to form a lower knife bed for the inverted knife.- An L- shaped bar d8 bolted in place by the bolt 58 securing the inverted knife fills-the space between this knife and the top of the-casing 31'.

The surfaces under the stationary knives ti are accurately machined and scraped so that when the knives are securely bolted in place in the recesses 22 and tilt will be impossible for baffie 62in the chute opening'serves .to deflect. the discharged material forward," allowing more powdered plastic material to work underneath the knives and become lodged between'the knives and their supporting surfaces or seats. Similarly the surfaces beneath the rotor knives 2? are scraped to fit these knives which, in addition, are well fitted at the back where they contact the rotor so that no material can lodge underneath, or at the back'sides, of therotor knives. f Mounted on suitable ledges" inside the lower end casing 3i and readily removable therefrom when the lower casing is disassembled from the main frame housing 29, as indicated in Fig. 6, is an arcuate bottom screen 59 'of any desired mesh. The'curvature of the inner face of the screen 56 is concentric with the cutting circle of the rotor knives 21 and the screen is slightly spaced therefrom and forms the bottom of the cutting chamber of the machine. In practice,'a set of interchangeable screens of different mesh may be employed so that the plastic material being cutwill be held back inthecutting chamber until it is chopped to a desired particle sizeto pass through the screen.

The screenis securely held in'positionby lugs.

5i and 52 at the forward closed end of the lower end casing-3i, see Fig; 5, and by a pin 53 at the other end of the lower end casingsl, the pin 53 extending through a hole 54 in an ear Edwelded or otherwise securedto theunder side of the screen 50 when the casing is pushed back axially. The pin 53 is fixedly secured bya' dowel to the main frame housing 20 and, when the'lower end casing 3! is removed from the machine as depicted in Fig. 5, this pin no longer engages the ear 55 underneath the screen but instead pro lifted up and the screen swung sidewise until this edge isreceived in the groove58 in the inner face of the side wall it i of the casing 3!. The screen 50 is then swung upwardly about this edge rubber, le

as apivot and lifted out between the stationary versal ofthesesteps. 1 Y, r Thelower end casing 3|. is provided tensionll2 of thetable member"! 5... An inclined room to insert alarge drum or other container member ll .butinstead it is secured to themachine framehousinglfi solely by the dowel bolts 33 and this overhung extension i2 merelyserves the purpose of supporting the Weight o-flthe lower end casing while the workman dismantling the machine is unscrewing .the two large bolts 33 that serve to attach the lower end casing 3! .to the.-

main frame housing 26 of the machine 7 Y The operation of themachine is as follows: As-

sume a screen 56 of the desired mesh to be inp-lace in the lower end casing 31. The plastic material to be cut is then introduced into the hopper 39 and passes therefrom" intothe l'cutting chamber 35. As soon as theplastic material is chopped to the desired particle sizes to pass through the screen Shit is dischargedfromthe conduit 6t) and through the chute opening Bl into'a drum. barrel or other container.. After a batch of the plastic majterial h'as been processed thelinterior of the cutting chamber may be made readily accessible for the purpose of cleaning, as fo-r the removal and sharpening of 'theknives or for the removal and the substitution for the'screen 50 of another screen having a greater or lessnum her of holes, either by unloosem'ng and swinging aside the swing bolts Stand removing the upper vend casing 32 and hopper 39 together as ax-unit or by first dismantlingthe hopper. 3:? by releasing the swing bolts 3! and then 'removin'gtheupper. endcasing 32.

shown in Fig. 3 to that depicted in Fig. 5 thereby affording easy access to the stationaryknives M7, screen 56 and other parts which are carried'by the lower end casing 3|.

While the invention has been particular reference to the cutting of. plastics it will'b-e understood that it is not limited to amachine for operating upon said types of materials, as the machine is suitable for cuttingchopping,

granulating or shredding toa predetermined fine; ness. a widevariety ofj materials such as--grain;"

athers, barleroots', tobacco,- paper, rag s,;1

Various modifications will be apparent from the foregoing description to those skilled in the art,i'

of' said housing', and disp SedaboVesaid over? I V hangingsupport, knives'carried by said overhanging end portion ofsaid rotor shaft forming a rotary cutter, an end casing on said overhanging support enclosing and forming a cutting Chain- 1 her about saidrot'atable knives, said casing com- Insertion of thei screen is accomplished by-reewith a dc liveryconduit 60 which: dischargesthe cut' andscreenedplastic'material into agchute opening, 6! beneaththe casingtl and formed inthe ex In-both instanceathe removal 7 ofthe lower end casing 3! then is effected by une screwing the two large bolts 33 and sliding the v lower casing 31 bodily to the right of the position x described with cutter in cooperative relation thereto,--a screen beneath and spaced from saidrotary cutter and supported by said lower end casing member, and

means detachably securing and accurately lo: eating said lower end casing on the end of said housing,i said lower end casingresting on but being unattached to said overhang ng support and, when disconnected from said hearing hous ing, being removable in a direction axially of said rotary cutter for cleaningflof the machine.

, 2;In a rotary cutting or granulating machine, an overhanging support, a main bearing housing, a rotor. shaft journaled in said housing, a knife head integral with said rotor shaft in overhang ing relationship with respect to one end of said housing, knives carried by said knife head, a casing on said overhanging support composed .of

separable upper and lower end casingslenclosing said rotor knives, a pair of opposed stationary knives in said lower end casing arranged to coact with the knives on the knife rotor, a curved screen insaid lower end casing beneath and spaced from said rotor knives, saidscreen form. ing with the interior wall surfaces of said upper end casing a cutting chamber about and spaced from said rotor knives, a feed hopper on the up per end casing arranged to discharge the mate.-

rial to be cut through said upper end easing into passing asaadsa for cleaning of the machine, 7

iii)

and slidably supported thereby for removal bodily in an axial outwardly direction to facilitate cleaning of the machine.

3. In a rotary cutting or granulati-ng machine,

, anoverhanging support, a main bearing housing,

a rotor shaft journaled in said housing, a'knife head integral with said rotor shaft in overhanging relationship with respect toone endoi said housing, knives carried by said knife head, a casing on said overhanging support, composed of separable upper and lower end casings enclosing said rotor knives, a pair of opposed stationary knives in said'lower end casing arranged to coact with the knives on the knife rotor, a curved screen; in said lower end casingbeneath and spaced 'from'said rotor knives, said screen-form ing with said upper end casing a cutting chamber aboutarid spaced from said'rotor knives,

,a feed hopperarranged to discharge the material to be cut through said upper end easing into said cutting chamber, chute means for discharging and deflecting the cut material forwardly from said lower end casing after" passing through said screen, swing bolts demountably securing said upper and lower end casings together, and

fastening devices removably securing and accu- V ratel'g, locating said lower end casing to the endof said main bearing housing, said fastening-devices consisting of a pair of large horizontal dowel bolts which not only serveto attach said lower end casing to said main bearing housing but also act as dowels for accurately positioning saidylow er end ng w h respe t to saidthousine and for i s i g a t e adjustment, ofthe stationary 4. in combination, a base, a table mounted pon said base of greater length than the base and overhanging one end thereof for a cOnsideI- able distance, and a rotary. cutting machine monnted u on the e d p rtion of said t l present-ins the ov rhan in part thereof, aid cut aid rotor knives operate on the material to be out, said lower end casing having knives project ing inwardly thereof from opposite sides of said rotary cutter in cooperative relation thereto, said lower end casing being unattached to the overhanging part of said table, and means detachably securing and accurately locating said lower end casing on the end of said main bearing hous ing so that when disconnected therefrom the lower end casing memberwill be supported entirely by said overhanging portion ofsaid table as the casing is slidably moved thereon in being removed from the machine in an ,endwise directionthere from. j

5. In combination, a. base, a table mounted upon said'base of greater length than the base and overhanging one end thereof for a consider.- able distance, ,a rotary cutting machine mounted upon the .endportion of said table presenting the overhanging'part thereof, and driving means operatively connected to said cutting machine and ounted upon theother end portion of said table, said cutting machine comprising a main bearing housing l fixedly secured to said table, a rotor shaft rotatably mountedin said housing and having an end portion extending outwardly in over hang ng relation ip to ne end'of sai housin to form a knife head, knives carried by said knife head forming a rotary cutter, an end casing on said overhanging partof the table enclosing said rotary cutter and composed of upper and lower separable casing members constructed and ar.- ranged to form a cutting chamber within which said rotor knives operate on the material to be out, said lower end casing havin two knivespro' jecting inwardly from opposite sides of said rotary cutter in cooperative relation thereto, said lowerend casing being unattached to said table, two dowel bolts detachably securing 'saidlower end casing to and accurately locating iton one end of said main bearing housingso that when said lower end casing is disconnected therefrom it will be supported entirely by said overhanging portion of said table as the lower end casing removed from themachine in an endwise direction therefrom, and a chute in said overhanging part'of the table constructed and arrangedto deflect the cut material forward as it passes downwardly from said cutting chamber.

e u new I- 

